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bpo-44471: Change error type for bad objects in ExitStack.enter_context() (GH-26820)

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A TypeError is now raised instead of an AttributeError in
ExitStack.enter_context() and AsyncExitStack.enter_async_context()
for objects which do not support the context manager or
asynchronous context manager protocols correspondingly.
This commit is contained in:
Serhiy Storchaka 2021-06-29 11:28:15 +03:00 • committed by GitHub
parent 20a88004ba
commit 6cb145d23f
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6 changed files with 91 additions and 8 deletions
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34
Lib/test/test_contextlib_async.py
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@ -483,7 +483,7 @@ class TestAsyncExitStack(TestBaseExitStack, unittest.TestCase):
1/0
@_async_test
async def test_async_enter_context(self):
async def test_enter_async_context(self):
class TestCM(object):
async def __aenter__(self):
result.append(1)
@ -504,6 +504,26 @@ class TestAsyncExitStack(TestBaseExitStack, unittest.TestCase):
self.assertEqual(result, [1, 2, 3, 4])
@_async_test
async def test_enter_async_context_errors(self):
class LacksEnterAndExit:
pass
class LacksEnter:
async def __aexit__(self, *exc_info):
pass
class LacksExit:
async def __aenter__(self):
pass
async with self.exit_stack() as stack:
with self.assertRaisesRegex(TypeError, 'asynchronous context manager'):
await stack.enter_async_context(LacksEnterAndExit())
with self.assertRaisesRegex(TypeError, 'asynchronous context manager'):
await stack.enter_async_context(LacksEnter())
with self.assertRaisesRegex(TypeError, 'asynchronous context manager'):
await stack.enter_async_context(LacksExit())
self.assertFalse(stack._exit_callbacks)
@_async_test
async def test_async_exit_exception_chaining(self):
# Ensure exception chaining matches the reference behaviour
@ -536,6 +556,18 @@ class TestAsyncExitStack(TestBaseExitStack, unittest.TestCase):
self.assertIsInstance(inner_exc, ValueError)
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
@_async_test
async def test_instance_bypass_async(self):
class Example(object): pass
cm = Example()
cm.__aenter__ = object()
cm.__aexit__ = object()
stack = self.exit_stack()
with self.assertRaisesRegex(TypeError, 'asynchronous context manager'):
await stack.enter_async_context(cm)
stack.push_async_exit(cm)
self.assertIs(stack._exit_callbacks[-1][1], cm)
class TestAsyncNullcontext(unittest.TestCase):
@_async_test